I think most people render to TIFF output, but I personally prefer BMP, both are loss-less. I'd only convert to .jpg for posting to the galley to keep the size down. Do all your postwork in loss-less format up to final posting or you'll loose quality each time to save and re-open it as a .jpg.

Render bigger than 1024 x 768 as most people's monitors are at resolutions much higher these days and it will look too small. GIMP is a good free image viewing and manipulation program if you don't have anything better.

All the best.